When you first said blurry I was thinking of it going to a lower resolution, but those lines in the pic on that thread you linked are an issue that was common for some people after waking the display from a sleep mode. I think for some a reboot fixed it, and until a future driver fixes it that's probably the best thing you can do for now. You should report that to Nvidia or post it on their forums for bugs/troubleshooting though, to add another voice and perspective on the issue which might help it be addressed sooner. I was reading about display ports and older vbios, and nvidia had a flasher utility for it but those were for blackscreen issues though with display port 1.4 I think. If you also had issues on other ports, then it could be the monitor, but it's also worth trying new cords or higher quality if you're able first too, and while on single monitor setup just to be sure. And then let it sleep again a few times and see how that goes.